Sulphate of potash (SOP) hopeful Trigg Mining (ASX: TMG) has begun drilling at its flagship Lake Throssell project in Western Australia.
The air core holes will be the first ever drilled to depth at Lake Throssell and will target the aquifer within the recently discovered palaeovalley underlying the salt lake.
In August Trigg, which holds ground lying east of Laverton, announced it had discovered the large-scale palaeovalley, a structure defined as a remnant of an inactive river or stream channel that has been filled or buried by younger sediment.
Then in September, the company lodged a new tenement application to enlarge its Lake Throssell to 937sq km.
The new ground application includes interpreted extensions to the south of the recently discovered palaeovalley, including a large interpreted bend in the paleochannel.
Previously, Trigg’s Lake Throssell SOP project covered about 694sq km of granted and pending tenements, within which there is 190sq km of salt-lake playa and 70km of underlying interpreted palaeochannels.
Trigg has said previously that the most prospective portion of the palaeovalley sequence (the thalweg, or deepest part of the ancient riverbed, in some places 2km wide) is most likely to host sand-rich aquifers, which in turn contain the potassium in brine.
Trigg aiming for second resource estimate
The project is located 170km east of Laverton on the Great Central Road connecting Laverton, WA to Alice Springs in the Northern Territory.
Trigg has described the new drilling program as “pivotal”.
Managing director Keren Paterson said drilling the basal aquifer at Lake Throssell has been the company’s primary focus since acquiring the SOP projects and listing on the ASX in October 2019.
“The results of this program are expected to provide sufficient detail to calculate an inferred mineral resource,” she added.
This would be the second mineral resource estimate since listing and will put Trigg “on a clear path towards the development of a significant new sulphate of potash production hub east of Laverton,” Ms Paterson said.
Earlier, the company reported high-grade SOP near the surface of the salt lake.
Competition for rigs delays resource estimate
Ms Paterson noted competition for drill rigs has been strong during the quarter in WA.
This has delayed the start of the Lake Throssell drilling program and, as a result, the new mineral resource estimate has been put back to the first quarter of 2021.
The state and federal governments are sealing the Great Central Road to establish the Outback Highway, connecting WA to the NT and Queensland. Work on the first 40km is under way.